CODEWITHSUNDEEP
rlist
Zhiqiang Wang
Zhiqiang Wang

Reputation: 6759

Manipulate list components

To generate a new combination of a list of names. I generated a list with the following R code: 

names1 <- c("A", "B", "C")
lst <- lapply(1:length(names1), function(x) combn(names1, x))
lst

> list
[[1]]
     [,1] [,2] [,3]
[1,] "A"  "B"  "C" 

[[2]]
     [,1] [,2] [,3]
[1,] "A"  "A"  "B" 
[2,] "B"  "C"  "C" 

[[3]]
     [,1]
[1,] "A" 
[2,] "B" 
[3,] "C"

Now, I would like to turn this list into a vector with the following 7 components, just like this one: 

newlst <- c("A", "B", "C", "A, B", "A, C", "B, C", "A, B, C")

In other words, I would like to combine the values within each column into one component of the new vector. unlist(lst) would not work as it produces 12 individual As, Bs, and Cs without any combinations. Any suggestions would be appreciated.

Upvotes: 0

Views: 40

Answers (1)

Sotos
Sotos

Reputation: 51582

The function combn takes a function. So if you pass toString and unlist you will get your output, i.e.

unlist(lapply(1:length(names1), function(x) combn(names1, x, toString)))
#[1] "A"       "B"       "C"       "A, B"    "A, C"    "B, C"    "A, B, C"

Upvotes: 4

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